I've seen people who release their Pokémon if they realize they don't have perfect IVs. Come on, that's almost impossible! I am only strict with the IVs of the stat I know I'm going to rely on mostly. For example, I just started training a Dragonite, its IVs are:
Special Attack 24
Special Defense 4
Even when its HP and Special Defense suck, I'm very happy with its Defense and even more with its Attack because I'm going to have him as a physical attacker and paralyzer (it has Outrage, Earthquake, Brick Break and Thunder Wave).
So, are you strict when it comes to IVs when EV training? Do you ditch Pokémon who don't have almost perfect or totally perfect IVs?